What is a Quantum Dot TV?

The latest buzzword in TVS is Quantum Dot technology.  To understand it we need to understand how LCDs TVs already work.

LCD – These work by having a backlight source (typically a bunch of LEDs) which shines through red, green and blue filters for each dot or pixel.  To create white, all the filters are shown in their correct colour.  To create black, the filters are all switched to black preventing light from passing through.  This creates a problem – the backlight has to be bright enough to make the whites stand out, but dull enough to not force its way through a black pixel.  Therefore contrast on LCDs is a huge issue which brought upon technologies such as ‘dynamic contrast’ and ‘local dimming’ as a poor attempt to bring them in line with the ageing Plasma technology.

Back to Quantum Dot, these are essentially an LCD TV, the Quantum Dot only refers to the backlight that is used.  The white required for the backlight is commonly created using blue LEDs with a yellow phosphor, which when combined create something close enough to white.  Where Quantum Dot differs is it uses regular blue LEDS which then shine on to a diffuse panel made up of two different sized quantum dots.  These dots take the blue light in and spit out red and green light which when combined with the original blue light of the led (RGB) creates a more accurate white than was previously possible.  Due to the more accurate wavelengths of the red, green and blue being created the LCD can filter these easier in turn creating slightly richer colours, and deeper blacks.  Still however suffering from the common backlight issues that plague ordinary LCDs as mentioned above.

It’s not OLED, but its a step in the right direction.